Notification in All Version Kotlin

    lateinit var notification: NotificationCompat.Builder
    lateinit var manager: NotificationManager
    val channel = "NotificationTest"
    lateinit var notificationChannel: NotificationChannel
    
    
     manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            notificationChannel = NotificationChannel(channel, "notification", NotificationManager.IMPORTANCE_DEFAULT)
            manager.createNotificationChannel(notificationChannel)
        }

        notification=NotificationCompat.Builder(this,channel)
                .setContentTitle("mohosyny")
                .setContentText("this is for test")
                .setAutoCancel(true)
                .setSmallIcon(R.mipmap.ic_launcher)


manager.notify(1,notification.build())